Display system

ABSTRACT

A display system including a display device and a light combining device is provided. The display device includes a first display region and a second display region. The light combining device has a first surface and a second surface opposite to the first surface. The first surface is capable of reflecting a first light beam from the first display region to an observing region for forming a first virtual image. The second surface is capable of reflecting a second light beam from the second display region to the observing region for forming a second virtual image. A curvature of the first surface is different from a curvature of the second surface, and a position of the first virtual image is different from a position of the second virtual image.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of and claims thepriority benefit of U.S. application Ser. No. 14/568,119, filed on Dec.12, 2014, now allowed. The entirety of the above-mentioned patentapplication is hereby incorporated by reference herein and made a partof this specification.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention generally relates to an optical system and, in particular,to a display system.

2. Description of Related Art

In modern society, requirements for vehicles include not only those forthe vehicles' performance, and attention has also begun to be paid tothe vehicles' interior and safety equipment. With the help of technologyproducts nowadays (e.g., in-car voice navigation system, voice-basedcollision warning system, etc.), the incidence of accidents caused bydrivers in states such as long-time drowsy driving, distracted and so onhas indeed dropped. In the meantime, however, since a non-voiceinformation display apparatus is generally mounted on a dashboard, whenthe driver lowers their head to watch the apparatus, driving safety islikely to be affected.

As a result, a display device that can less reduce the attention of thedriver, can reduce the fatigue of the driver, and can increase thedriving safety is required to be developed.

SUMMARY OF THE INVENTION

Accordingly, the invention is directed to a display system which canenable a driver to more quickly focus his or her eyes on the virtualimage formed by the display system and to reduce the fatigue of thedriver.

According to an embodiment of the invention, a display system includinga display device and a light combining device is provided. The displaydevice includes a first display region and a second display region. Thelight combining device has a first surface and a second surface oppositeto the first surface. At least one part of a first light beam from thefirst display region is reflected by the first surface to an observingregion so as to form a first virtual image. At least one part of asecond light beam from the second display region penetrates through thefirst surface, is reflected by the second surface, penetrates throughthe first surface again, and is transmitted to the observing region insequence, so as to form a second virtual image.

According to an embodiment of the invention, a display system includinga display device and a light combining device is provided. The displaydevice includes a first display region and a second display region. Thelight combining device is configured to deflect at least one part of afirst light beam from the first display region to an observing region soas to form a first virtual image, and configured to deflect at least onepart of a second light beam from the second display region to theobserving region so as to form a second virtual image.

In the display system according to the embodiment of the invention,since the first virtual image and the second virtual image are formed, adrive can focus his or her eyes on one of the first virtual image andthe second virtual image at an appropriate distance. As a result, adriver can more quickly focus his or her eyes on the virtual image.Therefore, the response time of the driver is shortened, and the fatigueof the driver is reduced, so that the driving safety is increased.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention.

FIG. 1 is a schematic view of a display system according to anembodiment of the invention.

FIG. 2 shows the first virtual image and the second virtual image inFIG. 1.

FIG. 3 shows another part of the first light beam not transmitted to theobserving region in FIG. 1.

FIG. 4 shows another part of the second light beam not transmitted tothe observing region in FIG. 1.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

A head-up display (HUD) displays the information desired by the driverin front of the driver, so that the driver does not have to lower orturn his or her head distractedly, which thus enhances driving safety.Nonetheless, while driving a car, the driver focuses his or her eye atdifferent distances at different car speeds. In general, in high-speeddriving (e.g., driving on a highway), the driver focuses his or her eyeat a further distance in front of the car; in low-speed driving (e.g.,driving in an urban area), the driver has his or her eye on roadconditions within a shorter distance in front of the car. However, if animage distance between an image generated by the head-up display and thedriver's eye is single and fixed, and if the driver intends to view theinformation shown by the head-up display, whether in high-speed orlow-speed driving, the driver has to spend time focusing his or her eyeat the image distance at which the image is located. Such time forfocusing the eye delays the time that the driver notices the roadconditions in front of the car, and the fatigue of the driver is alsoincreased.

FIG. 1 is a schematic view of a display system according to anembodiment of the invention, FIG. 2 shows the first virtual image andthe second virtual image in FIG. 1, FIG. 3 shows another part of thefirst light beam not transmitted to the observing region in FIG. 1, andFIG. 4 shows another part of the second light beam not transmitted tothe observing region in FIG. 1. Referring to FIGS. 1-4, a display system100 in this embodiment may be a head-up display disposed inside thewindshield of a vehicle. The display system 100 in this embodimentincludes a display device 110 and a light combining device 120. Thedisplay device 110 includes a first display region 112 and a seconddisplay region 114. The light combining device 120 is configured todeflect at least one part of a first light beam B1 (e.g., a first partB1′ of the first light beam B1) from the first display region 112 to anobserving region R so as to form a first virtual image I1, andconfigured to deflect at least one part of a second light beam B2 (e.g.,a first part B2′ of the second light beam B2) from the second displayregion 114 to the observing region R so as to form a second virtualimage 12.

Specifically, the light combining device 120 has a first surface 122 anda second surface 124 opposite to the first surface 122. At least onepart of the first light beam B1 (e.g., the first part B1′ of the firstlight beam B1) from the first display region 112 (e.g., an upper displayregion) is reflected by the first surface 122 to the observing region R,where at least one eye of a driver is located, so as to form the firstvirtual image I1. At least one part of the second light beam B2 (e.g.,the first part B2′ of the second light beam B2) from the second displayregion 114 penetrates through the first surface 122, is reflected by thesecond surface 124, penetrates through the first surface 122 again, andis transmitted to the observing region R in sequence, so as to form thesecond virtual image 12. Each of the first virtual image I1 and thesecond virtual image 12 may contain the information desired by thedriver.

In this embodiment, the display device 110 may be a liquid crystaldisplay, an organic light-emitting device display, a light-emittingdevice display, or any other appropriate display. The light combiningdevice may be made of a transparent material, so that light from anobject in front of the vehicle can penetrate through the light combiningdevice and be transmitted to the eyes of the driver. The first surface122 and the second surface 124 are curved surfaces. In this embodiment,the first surface 122 and the second surface 124 are freeform surfacesor aspheric surfaces. Moreover, in this embodiment, the first surface122 is a concave surface, and the second surface 124 is a convexsurface. As a result, each of the first surface 122 and the secondsurface 124 may serve as a concave mirror, and each of the first virtualimage I1 and the second virtual image 12 is thus an enlarged virtualimage. In this embodiment, the slope variation of the first surface 122is different from that of the second surface 124.

In the display system 100 in this embodiment, since the first virtualimage I1 and the second virtual image 12 are formed, a drive can focushis or her eyes on one of the first virtual image I1 and the secondvirtual image 12 at an appropriate distance. As a result, a driver canmore quickly focus his or her eyes on one of the first virtual image I1and the second virtual image 12. Therefore, the response time of thedriver is shortened, and the fatigue of the driver is reduced, so thatthe driving safety is increased.

In this embodiment, the first surface 122 is between the second surface124 and the observing region R, the second surface 124 is disposedbetween the first virtual image I1 and the first surface 122, and thesecond surface 124 is disposed between the second virtual image 12 andthe first surface 122. Moreover, the first virtual image I1 is betweenthe second virtual image 12 and the light combining device 120, and thefirst virtual image I1 is between the second virtual image 12 and thesecond surface 124.

In this embodiment, the display system 100 further includes a controlunit 140 configured to switch the display device 110 to a first state(as shown in FIG. 3) and a second state (as shown in FIG. 4). In thisembodiment, the display device 110 is electrically connected to thecontrol unit 140. When the display device 110 is switched to the firststate (as shown in FIG. 3), the first display region 112 emits the firstlight beam B1 and the second display region 114 does not emit the secondlight beam B2. Consequently, the first virtual image I1 is formed, andthe second virtual image 12 is not formed. When the display device 110is switched to the second state (as shown in FIG. 4), the second displayregion 114 emits the second light beam B2 and the first display region112 does not emit the first light beam B1. Consequently, the secondvirtual image 12 is formed, and the first virtual image I1 is notformed. Therefore, in high-speed driving, the control unit 140 mayswitch the display device 110 to the second state to form the secondvirtual image 12 which has a larger distant from the observing region R,so that the driver can focus his or her eye quickly on the secondvirtual image 12. Moreover, in low-speed driving, the control unit 140may switch the display device 110 to the first state to form the firstvirtual image I1 which has a shorter distant from the observing regionR, so that the driver can focus his or her eye quickly on the firstvirtual image I1.

In this embodiment, the control unit 140 is configured to receive anexternal signal S1 and determine to switch the display device 110 to thefirst state or the second state according to the external signal S1. Theexternal signal S1 may include a signal from a radar, a signal from acamera configured to detect at least one eye of a user, a signal from acamera configured to detect a front car, or a combination thereof.Specifically, a sensing unit 150 may be electrically connected to thecontrol unit 140 to help the control unit 140 determine that the vehicleis at a high speed or a low speed. The sensing unit 150 may be a radarconfigured to detect a front car, a camera configured to detect theinterval between the eyes so as to determine the distance the eyes focuson, a camera (e.g., an infrared camera) configured to detect a front caror a combination thereof.

Referring to FIGS. 3 and 4, the display system 100 may further includean optical element 130 disposed on paths of the first light beam B1 andthe second light beam B2 between the display device 110 and the lightcombining device 120. The optical element 130 may include a curvedmirror, a lens, a plane mirror, or a combination thereof. In FIGS. 3 and4, a curved mirror is exemplarily shown. For simplicity, FIG. 1 does notshow the optical element 130 of the display device 110. However, in someother embodiment, the display device 110 may not include the opticalelement 130.

In this embodiment, as shown in FIG. 3, the first part B1′ of the firstlight beam B1 from the first display region 112 is deflected by thelight combining device 120 to the observing region R so as to form thefirst virtual image I1, while a second part B1″ of the first light beamB1 is deflected by the light combining device 120 toward a directiondeviating from the observing region R. Specifically, in this embodiment,the first part B1′ of the first light beam B1 from the first displayregion 112 is reflected by the first surface 122 to the observing regionR, while the second part B1″ of the first light beam B1 penetrates thefirst surface 112, is reflected by the second surface 124, penetratesthrough the first surface 112 again, and is transmitted toward adirection deviating from the observing region R in sequence, e.g.,transmitted to a region below the observing region R. As a result, thefirst virtual image I1 may not be interfered with by the second part B1″of the first light beam B1.

On the other hand, as shown in FIG. 4, the first part B2′ of the secondbeam B2 from the second display region 114 is deflected by the lightcombining device 120 to the observing region R so as to form the secondvirtual image 12, while a second part B2″ of the second beam B2 from thesecond display region 124 is deflected by the first combining device 120toward a direction deviating from the observing region R. Specifically,in this embodiment, the first part B2′ of the second beam B2 from thesecond display region 114 penetrates through the first surface 122, isreflected by the second surface 124, penetrates through the firstsurface 122 again, and is transmitted to the observing region R insequence, while the second part B2″ of the second beam B2 from thesecond display region 124 is reflected by the first surface 122 toward adirection deviating from the observing region R, e.g., transmitted to aregion above the observing region R. As a result, the second virtualimage 12 may not be interfered with by the second part B2″ of the secondlight beam B2. For simplicity, the second part B1″ of the first lightbeam B1 and the second part B2″ of the second light beam B2 are notshown in FIG. 1, but are shown in FIGS. 3 and 4, respectively.

In the display system according to the embodiment of the invention,since the first virtual image and the second virtual image are formed, adrive can focus his or her eyes on one of the first virtual image andthe second virtual image at an appropriate distance. As a result, adriver can more quickly focus his or her eyes on the virtual image.Therefore, the response time of the driver is shortened, and the fatigueof the driver is reduced, so that the driving safety is increased.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of theinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the invention coversmodifications and variations of this invention provided they fall withinthe scope of the following claims and their equivalents.

What is claimed is:
 1. A display system comprising: a display devicecomprising a first display region and a second display region; and acombiner having a first surface and a second surface opposite to thefirst surface, wherein the first surface is capable of reflecting afirst light beam from the first display region to an observing regionfor forming a first virtual image, and the second surface is capable ofreflecting a second light beam from the second display region to theobserving region for forming a second virtual image, wherein a curvatureof the first surface is different from a curvature of the secondsurface, and a position of the first virtual image is different from aposition of the second virtual image; wherein the combiner is not awindshield; and wherein the observing region and the combiner are atdifferent heights, respectively.
 2. The display system according toclaim 1, wherein each of the first surface and the second surface is anaspheric surface or a free-form surface respectively.
 3. The displaysystem according to claim 1, wherein the first surface is capable ofbeing penetrated through by at least one part of the second light beamfrom the second display region, the second surface is capable ofreflecting the at least one part of the second light beam from the firstsurface, and the first surface is capable of being penetrated through bythe at least one part of the second light beam from the first surfaceand transmitting the at least one part of the second light beam to theobserving region for forming the second virtual image.
 4. The displaysystem according to claim 1, wherein the first surface is capable ofreflecting a first part of the first light beam from the first displayregion to the observing region, and the first surface is capable ofbeing penetrated through by a second part of the first light beam, thesecond surface is capable of reflecting the second part of the firstlight beam from the first surface, the first surface is capable of beingpenetrated through by the second part of the first beam from the secondsurface and transmitting the second part of the first beam toward adirection deviating from the observing region.
 5. The display systemaccording to claim 4, wherein the first surface is capable of beingpenetrated by a first part of the second beam from the second displayregion, the second surface is capable of reflecting the first part ofthe second beam from the first surface, the first surface is capable ofbeing penetrated through by the first part of the second beam from thesecond surface and transmitting the first part of the second beam to theobserving region, and the first surface is capable of reflecting asecond part of the second beam from the second display region toward adirection deviating from the observing region.
 6. The display systemaccording to claim 1, further comprising a control circuit configured toswitch the display device to a first state and a second state, whereinwhen the display device is switched to the first state, the firstdisplay region emits the first light beam and the second display regiondoes not emit the second light beam, and wherein when the display deviceis switched to the second state, the second display region emits thesecond light beam and the first display region does not emit the firstlight beam.
 7. The display system according to claim 6, wherein thecontrol circuit is configured to receive an external signal anddetermine to switch the display device to the first state or the secondstate according to the external signal.
 8. The display system accordingto claim 7, wherein the external signal comprises a signal from a radar,a signal from a camera configured to detect at least one eye of a user,a signal from a camera configured to detect a front car, or acombination thereof.
 9. The display system according to claim 1, furthercomprising an optical element disposed on paths of the first light beamand the second light beam between the display device and the combiner.10. The display system according to claim 1, wherein the first surfaceis a concave surface, and the second surface is a convex surface. 11.The display system according to claim 1, wherein the combiner is made ofa transparent material.
 12. The display system according to claim 1,wherein the combiner is capable of deflecting a first part of the firstlight beam from the first display region to the observing region forforming the first virtual image, the combiner is capable of deflecting asecond part of the first light beam toward a direction deviating fromthe observing region, the combiner is capable of deflecting a first partof the second beam from the second display region to the observingregion for forming the second virtual image, and the combiner is capableof deflecting a second part of the second beam from the second displayregion toward a direction deviating from the observing region.
 13. Thedisplay system according to claim 1, wherein the first display regionand the second display region belong to a same single display.
 14. Thedisplay system according to claim 1, wherein the combiner is below ahorizontal line of vision of an eye of a user, and the eye of the useris located in the observing region.
 15. A display system comprising: adisplay device comprising a first display region and a second displayregion; and a combiner having a first surface and a second surfaceopposite to the first surface, wherein the first surface is capable ofreflecting a first light beam from the first display region to anobserving region for forming a first virtual image, and the secondsurface is capable of reflecting a second light beam from the seconddisplay region to the observing region for forming a second virtualimage, wherein a curvature of the first surface is different from acurvature of the second surface, and a position of the first virtualimage is different from a position of the second virtual image; whereinthe combiner is one piece formed and not a windshield; and wherein theobserving region and the combiner are at different heights,respectively.
 16. The display system according to claim 15, wherein eachof the first surface and the second surface is an aspheric surface or afree-form surface respectively.
 17. The display system according toclaim 15, wherein the first surface is capable of being penetratedthrough by at least one part of the second light beam from the seconddisplay region, the second surface is capable of reflecting the at leastone part of the second light beam from the first surface, and the firstsurface is capable of being penetrated through by the at least one partof the second light beam from the first surface and transmitting the atleast one part of the second light beam to the observing region forforming the second virtual image.
 18. The display system according toclaim 15, wherein the first display region and the second display regionbelong to a same single display.
 19. The display system according toclaim 15, wherein the combiner is below a horizontal line of vision ofan eye of a user, and the eye of the user is located in the observingregion.
 20. A display system comprising: a display device comprising afirst display region and a second display region; and a combiner havinga first surface and a second surface opposite to the first surface,wherein the first surface is capable of reflecting a first light beamfrom the first display region for forming a first image, and the secondsurface is capable of reflecting a second light beam from the seconddisplay region for forming a second image, wherein a curvature of thefirst surface is different from a curvature of the second surface, and adistance between the first image and the combiner is different from adistance between the second image and the combiner; wherein the combineris not a windshield.